1. Field of the Invention
The present invention generally relates to wireless telecommunications. More specifically, the present invention relates to a system and method for asynchronously signaling and delivering data to a dormant wireless telecommunication device in a synchronous paging cycle on a wireless telecommunication system.
2. Description of the Related Art
In a wireless network, the users of wireless communication devices communicate over an over-the-air interface to a central computer. This may be done directly, as in the case of a wireless LAN in an office environment, or it may be done through cellular infrastructure equipment, as in the case of a wireless telephone application. One type of personal communication system is a push-to-talk (PTT) system between mobile wireless communication devices. A PTT communication connection is typically initiated by a single button-push on the wireless device that activates a half-duplex link between the speaker and each member device of the group and once the button is released, the device can receive incoming PTT transmissions once the button is released. In some arrangements, the PTT speaker will have the “floor” where no other group member can speak while the speaker is speaking. Once the speaker releases the PTT button, any other individual member of the group can engage their PTT button and they will have the floor.
A specific PTT group of recipient wireless devices for the communicating wireless device is commonly set up by the carrier and the wireless devices themselves do not allow the modification of the group, i.e. to include or drop individuals from the group, or to purposely direct a communication to be received by any fewer members than the entire group. A PTT group can provide a dispatch voice service that operates over standard commercial wireless infrastructure, with communication between endpoints occurs within virtual groups, wherein the voice of one “talker” is broadcast to one or more “listeners.” A single instance of this type of communication is commonly referred to as a dispatch call or simply a call. A call is an instantiation of a group, which defines the characteristics of a call. A group in essence is defined by a member list and associated information, such as group name or group ID. In the absence of a wireless multicast channel, each group is formed by the combination of separate point-to-point connections between each endpoint and group communication servers assigned to manage the call.
The typical PTT call involves two users who are rarely located within the same telecommunication sector such that communication and replication of the communication is propagated more easily over the existing telecommunication infrastructure. However, a small but very important fraction of push-to-talk calls involve a larger number of call participants, many of whom may also be located within the same sector; public-safety disaster scenarios are one example.
One problem arises in that a wireless telecommunication device may have to wait for a dedicated communication channel for the initial setup of a group communication, and such latency is readily apparent to the speaker and user. For wireless devices that are in a dormant state, i.e. no active broadcast channels, many systems periodically page the wireless device to make sure the system knows of the device's location, but such paging will be the next opportunity to push data out to the wireless devices and setup the PTT communication. It is thus to such a system and method that can reduce the latency for the setup of a PTT or direct group communication by setting up the group communication without waiting for the next page or setting up a dedicated channel that the present invention is primarily directed.